Described herein are photoinitiators that are soluble in various monomers for use in inks or toners, more particularly for use in ultraviolet (UV) curable inks.
For inks, coatings and toners, it is particularly desirable that the photoinitiator be odorless and not affect the color of the ink negatively, for example, by itself exhibiting a color upon curing.
IRGACURE® 2959 is an inexpensive commercially available photoinitiator. However, IRGACURE® 2959 has limited solubility, especially in monomers with alkoxy functional groups such as those used in UV curable inks and coatings. The solubility problem discussed herein leads to incomplete or inconsistent curing which affects image quality and durability. A photoinitiator with improved solubility is desired to address such potential issues.